网络为何存在

A network built for generality

One click, many messages

Streams and conversations

The design question and the course map

What most fundamentally distinguishes a computer network from the voice telephone network or the cable television network?

Before any page content is requested from a web server, what two exchanges must the browser complete, in order?

Why can a video-on-demand service buffer several seconds of video while a videoconference cannot?

Which of the four groups of network stakeholders is the traditional focus of network architecture and design?

In networking diagrams, what does a cloud symbol represent?

Why does a course on networks reason from first principles instead of cataloging today's protocols?

A single click on a web link can set in motion on the order of how many protocol messages, counting name lookup, connection setup, the request and response, and teardown? Give the nearest order as a word or digit.

Human factors research suggests a round-trip delay near how many milliseconds is the upper bound for a comfortable telephone-style conversation? Give the number.

Computer networks are built from general-purpose programmable hardware rather than being optimized for one application. What single word names this defining characteristic?

The two classes of video applications differ in their timing demands. Name the class that flows mostly one direction and tolerates startup delay but not stutters during playback.